Killer Octave Question

[Farrell]

> I have taken Model D bridges off that show a full 3/4" or more of 
> crown under the killer octave after fifty years. This same piano 
> probably had 1/8" of crown left on the longest ribs.

I thought Steinway soundboards were glued up with flat ribs. Where did the 1/8" of crown come from?

Terry Farrell
  
----- Original Message ----- 
[link redacted at request of site owner - Jul 25, 2015]
To: "Pianotech" <pianotech@ptg.org>
Sent: Saturday, April 12, 2003 10:33 PM
Subject: Re: Killer Octave Question


> Greg,
> 
> If the crown was created by being deformed for many years we would see 
> all piano makes with this feature. If this were so they all would have 
> crowned bridges. But clearly some makes have crown and others don't. 
> Maple bridges are quite stiff and I doubt that the crown I see could be 
> caused by the ribs pushing up. There is after all the force pushing down 
> from the string bearing. I can't say if every single piano from these 
> sources had the same amount of crown to begin with or whether sometimes 
> they would leave it out but I can say with reasonable certainty that 
> practically every one I have removed from a soundboad had at least some 
> crown. It is much more obvious on the larger pianos than the smaller 
> ones. I have taken Model D bridges off that show a full 3/4" or more of 
> crown under the killer octave after fifty years. This same piano 
> probably had 1/8" of crown left on the longest ribs.
> 
> I will try to get to your other question later. I am tiered from all the 
> back and forth with Ron's postings.
> 
> John Hartman RPT
> 
> John Hartman Pianos
[link redacted at request of site owner - Jul 25, 2015]
> Rebuilding Steinway and Mason & Hamlin
> Grand Pianos Since 1979
> 
> Piano Technicians Journal
> Journal Illustrator/Contributing Editor
> Greg Newell wrote:
> > John,
> >         I think I see your line of thought here. You have exclaimed that 
> > you rebuild with the same techniques you have found on the piano 
> > originally. Did I paraphrase that correctly? If so how can you tell if 
> > the original bridge was intended to be crowned from the factory or if it 
> > simply took on it's curvature from being mated to the soundboard panel 
> > for 'lo these many years? 
> 
> 
> 
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